containers

taubyte/go-simple-container

An abstraction layer over the docker api client. Goal: make it simple to use containers from go.

Installation

The import path for the package is github.com/taubyte/tau/pkg/containers.

To install it, run:

go get github.com/taubyte/tau/pkg/containers

Usage

Basic Example

import (
    ci "github.com/taubyte/tau/pkg/containers"
    "context"
)

ctx := context.Background()

// Create an new client
client, err := ci.New()
if err != nil{
    return err
}

// Using `node` image for our container
dockerImage := "node"

// Initialize docker image with our given image name
image, err := client.Image(ctx, dockerImage)
if err != nil{
    return err
}

// Commands we will be running
commands := []string{"echo","Hello World!"}

// Mount Volume Option 
volume := ci.Volume("/sourcePath","/containerPath")

// Add Environment Variable Option
variable := ci.Variable("KEY","value")

// Instantiate the container with commands we will run
container, err := image.Instantiate(
    ctx,
    ci.Command(commands),
    // options
    volume, 
    variable
)
if err != nil{
    return err
}

// Run container 
logs, err := container.Run(ctx)
if err != nil{
    return err
}

// Create new byte buffer 
var buf bytes.Buffer

// Read logs 
buf.ReadFrom(logs.Combined())

// Set output to the string value of the buffer 
output := buf.String()

// Close the log Reader
logs.Close()

Using Your Own Dockerfile

• Create a Dockerfile in a directory with any dependencies that you may need for the Dockerfile, the file must be named Dockerfile. This is case sensitive.

• run: $ tar cvf <docker_tarball_name>.tar -C <directory>/ .

• Docker expects Dockerfile and any files you need to build the container image inside a tar file.

  • Using embed:

  //go:embed <docker_tarball_name>.tar
  var tarballData []byte 
  
  imageOption := containers.Build(bytes.NewBuffer(tarballData))
  

  • Using a file:

  tarball, err := os.Open("<path_to>/<docker_tarball_name.tar>")
  if err != nil{
      return err
  }
  defer tarball.Close()
  
  imageOption := containers.Build(tarball)
  

• Create the image with a custom image name, and the the ImageOption

  • The image name must follow the convention <Organization>/<Repo_Name>:Version
  • All characters must be lower case

client.Image(context.Background(),"taubyte/testrepo:version1",imageOption)

Creating a Garbage Collector

import ( 
    "github.com/taubyte/tau/pkg/containers/gc"
    ci "github.com/taubyte/tau/pkg/containers" 
)

// Create new docker client 
client, err := ci.New()
if err != nil{
    return err
}

// Create a context with cancel func, calling the cancel func will end the garbage collector go routine.
ctx, ctxC := context.WithCancel(context.Background())

// Create new garbage collector
gc.New(ctx, gc.Interval(20 * time.Second), gc.MaxAge(10 *time.Second ))

Running Tests

If running tests for the first time, from directory run:

cd tests 
go generate

Then run

$ go test -v